The spatial and temporal expression of extracellular matrix proteins and their receptors are critical for normal tissue organization, development and growth. Conversely, abnormal expression of these extracellular proteins and receptors as a result of either genetic or acquired diseases often represents the pathologic basis for clinical illness. For example, many renal, pulmonary, hepatic, and skin diseases are characterized by abnormal deposition of extracellular matrix proteins leading to impaired function and healing. The purpose of these studies is to understand the molecular mechanisms by which genes for the extracellular matrix proteins and their receptors are regulated during normal development and in disease. Using a combination of molecular, cellular and physiologic techniques, we are evaluating normal and pathologic conditions associated with changes in the expression of extracellular matrix proteins and their receptors including normal fetal development, disordered renal growth typical of polycystic kidney disease and cancers of the kidney, and the increase in extracellular matrix proteins observed in diabetic nephropathy, cyclosporine toxicity, and with certain retroviral infections.